<!DOCTYPE html>
<html>
<head>
  <meta charset="UTF-8">
  <title>Document</title>
</head>
<body>
  <script>
    var arr = ['短跑', '接力', '短跑', '拔河', '跳绳', '接力', '拔河', '跳远'];
    function unique(arr) {
      var newArr = [];
      for (var i = 0; i < arr.length; i++) {
        if (newArr.indexOf(arr[i]) === -1) {
          newArr.push(arr[i]);
        }
      }
      return newArr;
    }
    console.log(unique(arr));
  </script>
</body>
</html>